Abstract:

Cancer remains a significant global public health challenge, with its incidence and mortality rates continuously increasing. Conventional cancer treatments, including chemotherapy, radiotherapy, and surgery, often entail severe side effects and potential drug resistance. This comprehensive review examines the pivotal role of probiotics in cancer prevention, treatment, and management, elucidating their underlying mechanisms and clinical applications. Probiotics, defined as beneficial microorganisms that colonize the human gastrointestinal tract and other mucosal surfaces, have emerged as potential adjuncts in cancer prevention and treatment. Their mechanisms of action include modulation of the tumor microenvironment (TME), enhancement of immune responses, and inhibition of carcinogenesis. In cancer prevention, probiotics can modulate the gut microbiota to inhibit carcinogen generation. For example, specific strains of Lactobacillus and Bifidobacterium have been shown to decrease the activity of enzymes involved in carcinogen production, such as β - glucuronidase and nitroreductase. Moreover, Probiotics and their metabolites, short-chain fatty acids (SCFAs) and indole compounds, play an antitumor role by regulating the tumor microenvironment such as regulating cancer-related gene expression, the PI3K-AKT signaling pathway, and the tryptophan-indole metabolic pathway. In the context of adjuvant therapy for malignant tumors, probiotics have exhibited inhibitory effects on various cancers in the digestive and reproductive systems. They can modulate the intestinal microenvironment, influence tumor cell proliferation and apoptosis, and ultimately suppress tumor growth. Additionally, probiotics can alleviate the adverse effects of cancer therapies. For example, they can mitigate chemotherapy - induced diarrhea and radiation-induced mucositis, and promote postoperative recovery by enhancing gut barrier function and reducing inflammation.This review provides a comprehensive and systematic synthesis of the research on the role of probiotics in the prevention and adjuvant treatment of malignant tumors. It delves into their potential mechanisms of action and explores their clinical applications, aiming to establish a solid theoretical foundation and practical guidance for the integrated management of cancer. Looking ahead, the integration of synthetic biology with probiotics offers substantial potential for cancer therapy. Advances in synthetic biology have enabled the enhancement of probiotics' anti-tumor efficacy through genetic engineering. Engineered strains, such as Escherichia coli Nissle 1917 and attenuated Salmonella typhimurium VNP20009, have shown potential in tumor-targeted therapy. When combined with emerging technologies like nanotechnology and photodynamic therapy, the application of probiotics in cancer treatment is expected to become more precise and effective. However, the safety and efficacy of engineered probiotics require further validation, particularly regarding the potential risks associated with long-term use. Future research should focus on personalized probiotic applications, the development of engineered strains, and their synergistic effects with other therapeutic modalities to advance this field. In conclusion, probiotics hold significant promise as adjuncts in cancer prevention and treatment, with the potential to modulate the TME, enhance immune responses, and alleviate treatment-related side effects. Further research is needed to fully elucidate their mechanisms of action and optimize their clinical application, thereby facilitating their integration into comprehensive cancer care strategies.

Key words: probiotics, intestinal flora, antitumor, tumor microenvironment

摘要：

癌症作为一种全球性公共卫生难题，其发病率和死亡率不断攀升。益生菌作为一种潜在的辅助防治恶性肿瘤的手段，近年来受到广泛关注。本文系统综述了益生菌在辅助防治恶性肿瘤方面的研究进展。在肿瘤预防方面，益生菌及其代谢产物可通过调控肠道菌群并抑制致癌物生成，调节免疫细胞，减轻炎症反应，降低癌症发生风险。此外，益生菌及其代谢产物短链脂肪酸（SCFAs）、吲哚类化合物通过调节肿瘤微环境如调节癌症相关基因表达、PI3K-AKT信号通路及色氨酸-吲哚代谢途径发挥抗肿瘤作用。在辅助治疗恶性肿瘤方面，益生菌对消化系统、生殖系统等多种肿瘤均表现出抑制作用，可通过调节肿瘤微环境中的多种成分和功能，影响肿瘤细胞的增殖和凋亡。益生菌在改善肿瘤治疗副作用方面也发挥积极作用，既可以缓解肿瘤放化疗副作用，如减轻口腔黏膜炎、放射性腹泻等，又有助于肿瘤术后恢复，改善肠道屏障功能，减轻术后的炎症反应。合成生物学技术的发展为益生菌的抗肿瘤应用提供了新方向。通过基因工程改造的益生菌，如大肠杆菌Nissle 1917和减毒沙门氏菌VNP20009，已在肿瘤靶向治疗中展现出潜力。结合纳米技术和光动力治疗等新兴手段，益生菌在肿瘤治疗中的应用将更加精准和高效。然而，工程菌的安全性和有效性仍需进一步研究。随着合成生物学技术的发展，通过深入探索益生菌抗肿瘤的作用机制、优化临床应用方案，并结合新兴技术手段，工程益生菌有望成为肿瘤综合治疗中的重要组成部分，为患者提供更加安全、有效的治疗选择。

关键词: 益生菌, 肠道菌群, 抗肿瘤, 肿瘤微环境